1. Field of the Invention
The present invention relates to binding and trimming booklets and more particularly to an apparatus and method of adding a flat cover signature to a single or collated signatures and head and tail trimming the booklets following center stitching prior to or following saddle folding.
2. Description of the Prior Art
Prior attempts to add a cover signature in register with a single or collated signatures moved past a cover signature hopper and transfer drum station by a tape conveyor have generally been unsuccessful. This invention accomplishes this function by a sensor actuated by the leading edge of a single or collated signatures which triggers a mechanical clutch angularly rotating the cover signature transfer drum.
U.S. Pat. No. 2,872,980 discloses a strip trimming apparatus which discloses rotating slitter blades trimming opposing sides of a strip wherein the angle of the cutting blades is adjusted with respect to the axis of the strip passing between the cutter in an attempt to prevent strip tail-out or a buckling inward of the strip material between the opposing cutter blades principally caused by the slitter blades constantly forcing the strip material inwardly.
U.S. Pat. No. 647,053 discloses a trimmer for wallpaper, or the like, teaching the value of different speeds for one pair of cutters relative to an opposed cooperating pair, however, in processing a single thickness of strip material support of the material between opposing blades is not as critical as when slitting or head and tail trimming multiple sheet booklets or folded material.
This invention overcomes the disadvantages of the above patents by correcting the tail-out problem at its source by clean cutting slitters which includes a lower pair of roating circular cutting blades or slitters at opposing ends of a booklet to be head and tail trimmed with an upper cooperating pair of circular blade slitters angularly rotated at a rate of rotation greater than the lower pair. Further, the invention provides a support for the bottom surface of the booklet being trimmed in the area between the infeeding rollers prior to slitting and between the slitter arbors and the next set of pull-out rollers which enhances the desired result, namely, clean cutting slitting.